Signal translating apparatus



19435;! H. .1. HASBROUCK, JR 2,326,460

SIGNAL TRANSLATING APPARATUS Filed Sept. 19, 1940 Ffiw. j. 7 1a 1 Harold; J Habrouc7i,Jn

Zhwentor v Patented Aug. 10, 1943 UNITED STATES PATENT OFFICE 2,326,460 SIGNAL TRANSLATING APPARATUS Harold J. Hasbrouck, Jr., Merchantville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application September 19, 1940, Serial No. 357,356

Claims. (01. 179-40041) v" a needle comprised of a rigid arm which extends downwardly toward the record to within about 3 2 of an inch of the record and in the lower end of which is suitably secured a thin wire of wear-resistant material, the wire being substantially L-shaped and being flexible both vertically and horizontally, that is, in planes both normal to and parallel with the record. The free end of the L-shaped wire extends downwardly for about %4 of an inch to provide the record groove engaging tip. Practically all motion is confined to this piece of wire, and while this form of needle has been found very satisfactory, there are certain cases in which it is desirable that the needle shall have greater stiffness in a plane normal to that of the record than in a plane parallel to the plane of the record, so that it will have sufllcient stiffness to support the weight of the pickup while retaining desired flexibility in a lateral direction.

The primary object of my present invention is to provide an improved phonograph needle which will accomplish this function.

More particularly, it is an object of my present invention to provide an improved phonograph needle which will faithfully follow the undulations of the record groove while serving as an adequate support for the pickup device of which it forms a part and at the same time transmitting the vibrations to the translating unit with great fidelity.

It is also an object of my present invention to provide an improved phonograph needle as aforesaid which is simple in construction and economical in cost.

In accordance with my present invention, I form the needle in part of a piece of elongated resilient stock of rectangular cross section having greater dimension in a plane normal to that of the record than in a plane parallel with the record. It will be obvious, therefore, that the needle will have greater stiffness in the first mentioned plane than in the second mentioned plane, wherefore it is capable of supporting the pickup while retaining lateral flexibility when made of appropriate dirtiensions. One end of the aforementioned needle part may be secured to the rigid arm heretofd're mentioned, and its other, or free, end is preferably provided with a loop or eye in which may be inserted a needle engaging element or tip of suitable material for long life.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, bothas to its organization and method of operation\ as well as additional objects\and advantages thereof, will best be understoodxfrom the following description of one embodiment thereof when read in connection with the accompanying drawing, in which Figure 1 is a fragmentary sectional view through a sound translating device constructed according ts my invention andincorporating the improved needle,

Figure 2 is a'top plan view of the needle itself, and

Figure 3 is a side elevation thereof.

Referring more particularly to the drawing, wherein similar reference numerals indicate corresponding parts throughout, I have shown, in

Fig. 1, a casing member I formed in two parts and preferably hermetically sealed to enclose a piezo-electric unit comprising a pair of piezoelectric crystals 3 of Rochelle salt or the like, with which are associated suitable terminal foils of conductive material in well known manner, the crystal unit 3 being spaced from the casing I by suitable blocks 5 of damping material. The casing I also carries a torsion yoke 1 within a rubber sleeve 9, the outer or free end of the torsion yoke 1 being provided with an opening iI at its outer end and being formed with .a yoke or clamp I3 at its inner end for firmly clamping one end of the crystal unit 3. The device thusfar described is more or less conventional and may be mounted upon a suitable pickup arm for movement over a disc phonograph record or tablet R in well known manner.

Removably received within the opening I I is a rigid arm or rod I5 which extends downwardly from the torsion yoke l substantially at right angles to the plane of the crystal unit 3. The rod I5 may be secured to the torsion yoke'l between a shoulder I! which is formed on the rod I5 and a nut I9 threaded onto the upper end thereof, the improved needle constituting my present invention being secured at one of its ends to the lower end of the rod I5. The needle consists of an elongated, resilient strip or shank portion 2|, preferably rectangular in cross section and having -a greater height h than thickness t, as clearly seen from Figs. 2 and 3, whereby the member 2| is more resilient in a plane parallel to the plane of the record R than in a plane normal thereto. 2| may-be made of spring steel and its thickness w may be of the order of .007" with its height approximately .012". At its outer, or free, end, the member 2| is formed with a circular loop or eye 23 the axis of which extends in a plane normal to the plane of the record and into which is preferably press fitted the cylindrical portion of a record engaging stylus or similar element 25 of jewel, metal or any other suitable material having a long playing life. To permanently secure the record engaging element 25 in the eye 23, a cap of solder 21 may be applied to the upper end thereof, thus closing. the eye and capping the same.

When the pickup device is in cooperative relation to the record R, the elongated member 2| occupies a position substantially parallel to the record disc. It will be obvious, from the foregoing description, that the needle is capable of supporting the pickup unit on the record disc R, since it is relatively still! in a plane normal to the plane of the record. At the same time, the needle is sufficiently flexible to enable it to faithfully follow the undulations in the record groove and to faithfully transmit to the crystal unit 3 through the rigid rod I5 the arcuate motion imparted thereto by the record groove about the axis of the yoke 1. Preferably, although not necessarily, the record engaging tip or element 25 extends to one side of the elongated member 2| at right angles thereto. However, if desired, the loop 23 may be so formed that the element 25 will extend from the member 2i at an angle greater than a right angle, while still remaining in a plane at right angles to the plane of the record. In any case, the needle unit constituted by the shank 2|, the needle tip 25 and the rod I5 may be easily removed from the pickup device by merelyremoying the nut 19, whereupon the rod I 5 may be slipped out of the opening ll.

Various other modifications of my present invention, as well as changes in the particular one described, are possible, as will be obvious to those skilled in the art. I therefore desire that my invention shall not be limited except insofar as is made necessary by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In a sound translating device for reproducing sound from a disc phonograph record, the combination with an eleetro-mechanical converter of a needle comprising a rigid motion transmitting part coupled to said converter, and a flexible member carried by and angularly re- The elongated member.

lated to said motion transmitting part, said memvber comprising a relatively elongated resilient element having a greater height than thickness dimension throughout its length whereby said element is more resilient throughout its length in the direction of its thickness than in the direction of its height, said element being adapted to occupy a position in operative relation to said record disc such that its height dimension is in a plane normal to that of said disc and its thickness dimension is in a plane normal to that of said first named plane whereby said element has greater resilience in said last named plane than in said first named plane, and a record engaging stylus carried by said element, said stylus extending from said member in said first named plane.-

2. In a sound translating device for reproducing sound from a disc phonograph record, the combination with an electromechanical converter of a needle comprising a rigid motion transmitting part coupled to said converter, and a flexible member carried by and normal to said motion transmitting part, said member comprising a relatively elongated, resilient element having a greater height than thickness dimension throughout its length whereby aid element is more resilient throughout its length in the direction of its thickness than in the direction of its height, said element being adapted to occupy a position in operative relation to said record disc such that it is substantially parallel to said disc with its thickness dimension disposed in a plane also parallel to said disc at all points along its length and with its height dimension disposed in a plane normal to that of said disc whereby said element has greater resilience in said parallel plane than in said normal plane, and a record engaging stylus carried by said member, said stylus extending from said element in said last named plane.

3. The invention set forth in claim 2 characterized in that said element is provided with a loop at one end, and characterized further in that said record engaging stylus is secured to said element in said loop.

4. The invention set forth in claim 2 characterized in that said element is provided with a loop at one end, andcharacterized further in that said record engaging stylus is press fitted into said loop.

5. The invention set forth in claim 2 characterized in that said element is provided with a loop at one end, characterized further in that said record engaging stylus is press fitted into said.lo0p, and characterized still further by the addition of a retaining cap over the upper end of said loop and said stylus, said cap retaining said record engaging stylus in said loop.

HAROLD J. HASBROUCK, J R. 

